Folding steel rule.



11. J. SIMPSON.

' FOLDING STEEL BULB.

APYLIOATION FILED APB. 29, 1909.

986,772. Patented 113114,1911.

'UNITED sTATEs PATENT ormoni.

ROBERT J. SIMPSON, 0F ATI-IOL, MASSACHUSETTS, ASSIGNOR TO L. S. STARRETT COM- IEANY, OF ATI-IOL, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

FOLDING STEEL RULE.

Specification of Letters Patent.

Patented Mar. 14, 1911.

To all whom 'it may concern:

Be it known that I, ROBERT J. SIMPSON, of Athol, in the county of Worcester and State of Massachusetts, have invented certain new and useful Improvements in Folding Steel Rules, of which the following is a specification.

This invention relates to folding rules and particularly to thin, folding, metal rules, and particularly to the locking of the joints of thin, folding, metal rules.

In the joining of the overlapped members of folding rules it is a matter of great importance that the joints be as flat and snug as possible in order to avoid the springing of the rule sections when the device is in folded or closed position. It is of particular importance that the locking of these joints be secured without an undue engagement of the joint construction and at the same time that the joint be relieved as far as possible from strain or racking tendency upon the actuations of the locking mechanism. To the end, therefore, of providing a locking joint which shall be capable of compact structure, which shall be sim le and so balanced as to avoid the strain 1n actuation, I have devised my present invention. In it I have provided a locking member so positioned upon the joint rivet as to avoid any loosening tendency of the joint and so balanced about the same as to maintain at all times a symmetrical bearing and tension. I have, further, provided for the locking of the joint in angular positions of the menibers and have, further, included various irnprovements in structure and detail, all of which will be more fully described in the specification which follows.

In this specification and in the drawings which form a part thereof like reference numerals are employed to indicate corresponding parts andv in the drawings Figure 1 is an enlarged plan view of my locking joint, Fig. 2 is a central longitudinal section of the same with the rivet and locking piece in elevation, Fig. 3 shows the adjacent ends of a pair of members to be united with the locking recess indicated thereon, Fig. 4: shows a lower plan view of the locking piece, and Fig. 5 is an edge view of the same.

5 and 6 are two members of a rule which is made up of a plurality of similar sections. Each section has one end similar to the end of the section 5 shown and an opposite end similar to the end of the section 6 as shown. These sections are pivotally connected by'a rivet 7 which passes through the opening 8 which is located in each end of each section. The opening 8 is punched concentric with the rounded adjacent end of each section member. Each section has a notch 12 cut centrally ofone of its rounded ends and a small opening 11 diametrically opposite to the rivet 7 passes and opposite down turned rounded points 10 which are adapted to be engaged simultaneously with 13 and 13 or 132 and 132. When the ends of the two sections, such as 5 and 6, are thus riveted together with the spring locking yoke 9, one end 10 of the yoke will pass through the opening 11, thus holding the yoke against rotation and permitting it to bear upon the upper face of the end of the section 5. The opposite end 10 rests in the notch 12 and is thus similarly held against rotation, while being permitted to rest upon the saine face and the section. Both points 10 travel in the circle which passes through the recesses 13, 132, 13', 132. On account of the mechanical possibilities this joint construction may be made from within while preserving strength and rigidity. When the joint is to be folded two sections, such as 5 and 6, are turned on the rivet 7 as a pivot. This starts the rounded end of the point 10 out of engagement with the recesses 13 and at the same time starts in an opposite direction the rounded tip of the opposite point 10 out of engagement with the recess 13. As these points ride up, over the edges of the recess the arms of the yoke 9 yield. As the pressure is equal, and equally balanced about the central rivet 7, and as the yoke 9 is not interposed between the members, there is no straining apart of the members and no racking or twisting of the members on the point of pivot. Both of these things would, of

course, happen if the structure were other- "wise as to either feature. My rule is, therefore, firmly locked in either closed, straight openor right angled positions. The joints in my rule are actually so strong as to impart to the rule when opened an unusual longitudinal rigidity and stiffness which makes it possible to handle even a three-foot rule of thin steel by one end without a buckling which interferes with its practical 'use and apparently without any strain upon the joints. The structure of my rule further makes possible an ease and smoothness in operation on account of the frictional contact of the rounded ends of the points 10 on the surface of the underlying section end.

The rule is suitably graduated and is preferably squared atthe ends of its terminal members.

Various modifications may obviously be made in the structure and operation of my device, all without departing from the spirit of my invention if within the limits of the appended claims.

What I therefore claim and desire to secure by Letters Patent is l. In aV folding rule, a plurality of rounded end members having suitable perforations and recesses a pivot stud uniting said ends and a locking piece comprising a A fiat double ended spring enlarged and perforatedcentrally to receive the pivot stud which unites the members, and formed at its ends with terminally rounded points offset to engage said recesses in adjacent members, substantially as described.

2. In folding rules, a plurality of flat members successively ,pivoted together at their overlapped ends one end of each mem- VVtheir similar rounded overlapping ends one end of each member being perforated on each side of the pivot hole and the other member formed with shallow concavities circumferentially registering with said perforations, in combination with a flattened spring open centrally for the passage of the pivot and having oppositely extending spring arms terminally offset to form equidistant points passing through the perforations in said first named member and rounded at their tips to bear upon the surface of the other member and to automatically engage and disengage said lconcavities therein substantially as set forth.

4t. In a folding rule, a pair of overlapping 70 sections, a headed pivot uniting the two, one of said members having locking recesses upon its inner face and the other of said members having openings regsterable therewith and a spring locking member mounted upon said pivot between said last named member and the pivot head and having its ends turned down through said openings to engage said recesses.

5. In a folding rule, a pair of overlapping sections, a hea ed pivot uniting the two, one of said members having locking recesses upon its inner face and the other of said members having openings registerable therewith and a double ended spring locking member outside of said members and having a central opening inclosing said pivot and having its ends down turned through said openings to engage said recesses.

6. In a folding rule, a pair of overlapping sections, a pivot uniting the two, and a resilient means on said pivot outside of said members for interlocking them in predetermined position.

7. In a folding' rule, a pair of overlapping 95 sections, one of said sections having a recess, a pivot uniting the two and a spring on said pivot outside of said members and having a. downturned end for engaging said recess to interlock said members in a predeterminedzposition.

Intestimony whereof I have afiixed my signature, in presence of two witnesses.

ROBE-RT J. SIMPSON.

itnesses WILLARD G. NIMs, FRANK E. WING.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents,

Washington, D. C. 

